OBJECTIVE: The scope of our investigation is designed to contribute to understanding details of the mechanism of catalysis by nucleic acid enzymes. The two classes of enzymes we have selected offer exciting opportunities as models for the recognition process between nucleic acids and enzymes involved in their synthesis and degradation. The experiments to be pursued are based directly on findings we have published in the area. Therefore, the experimental work required to attain the specific aims is well within the means of this laboratory. APPROACH: a. Characterization of different molecular weight forms of AMV DNA polymerase with an emphasis on the sequence of enzyme maturation and activity using 35S viral RNA. b. Chemical and biophysical experiments designed to elucidate the interactions between primer tRNATrp and AMV DNA polymerase. c. Assessment of chemical modification of 35S RNA. d. Purification and characterization of novel DNA endonucleases from A. tumefaciens. e. Attempts at crystallization of a restriction endonuclease (Bam H1).